Deformable non-round membrane assemblies

A deformable membrane assembly comprising:

• a fluid-filled envelope, one wall of which is formed by a distensible membrane;
• a resiliently bendable supporting ring that holds the distensible membrane around its edge under tension;
• a fixed support for the fluid-filled envelope;
• and
• a selectively operable device arranged to act between the resiliently bendable supporting ring and the fixed support for adjusting the pressure in the fluid-filled envelope, thereby to cause the distensible membrane to deform,
• wherein the resiliently bendable supporting ring comprises a plurality of ring elements, and the distensible membrane is sandwiched between two adjacent ring elements, thereby to balance torsional forces on the resiliently bendable supporting ring that result from the tension in the distensible membrane.

An article of eyewear comprising a deformable membrane assembly comprising:

• a fluid-filled envelope, one wall of which is formed by a distensible membrane;
• a resiliently bendable supporting ring that holds the distensible membrane around its edge under tension;
• a fixed support for the fluid-filled envelope;
• a selectively operable device arranged to act between the resiliently bendable supporting ring and the fixed support for compressing or expanding the fluid-filled envelope, thereby to cause the distensible membrane to distend in a convex or concave manner;
• wherein the resiliently bendable supporting ring comprises a plurality of ring elements, and the distensible membrane is sandwiched between two adjacent ring elements, thereby to balance torsional forces on the resiliently bendable supporting ring that result from the tension in the distensible membrane;
• wherein the fluid-filled envelope is flexible and comprises a rear wall opposing the distensible membrane and a peripheral side wall intermediate the distensible membrane and the rear wall, the peripheral side wall being flexible to allow the rear wall resiliently bendable supporting ring to be moved towards or away from each other for compressing or expanding the fluid-filled envelope;
• wherein the rear wall is rigid or substantially rigid;
• and
• wherein the distensible membrane, the rear wall and a fluid of the fluid-filled envelope are transparent such that the distensible membrane and the rear wall form an adjustable optical lens.